Originally Posted by coachster
Agreed. CO2 or propane grenades often appear to have some smoke. It will be the vapor plus a bit of silicone oil exiting just like a GBB.
Also, less likely the smoke you saw, but the BB's from a larger nade like a madbull king will look like a giant cloud coming at you
Powder shots in the xmpb4 are less than dramatic.
I only ever saw a "smoke" puff come out from xmpb4 so thats what I thought it was.